This application claims the priority of German Patent Document DE 101 30 401.3, filed on, Jun. 23, 2001, the disclosure of which is expressly incorporated by reference herein.
This invention relates to a torsion bar spring arrangement, particularly to a stabilizer arrangement, for a double-track vehicle, having at least one prestressed spring element which limits the introduction of force into the torsion bar spring or the stabilizer to a value defined by the prestressing force of the spring element. With respect to the technical environment, reference is made, for example, to European Patent Document EP 0 648 625 A1.
Stabilizer arrangements or generally torsion bar spring arrangements are generally customary in the case of double-track vehicles. For example, in order to limit the effect of the stabilizer to the necessary rolling forces, it has been suggested to arrange prestressed spring elements with or without damping as tension or pressure rods between the stabilizer ends and the wheel axles of the vehicle.
An aspect of certain preferred embodiments of the invention relates to how damage can be avoided on a torsion bar or stabilizer arrangement which are caused by an introduction of force into the torsion bar or stabilizer arrangement which significantly exceeds the normal value occurring in the driving operation. This is particularly important when at least two parts of the torsion bar spring can be rotated with respect to one another by way of an actuator because this actuator must then be protected from an overloadxe2x80x94caused by an unusually high introduction of external force into the torsion bar spring arrangement.
This aspect may be achieved in that the spring element acts as an overload protection such that, when a force is introduced which significantly exceeds the prestressing force, the torsion bar spring arrangement would be damaged without this spring element. Advantageous developments and further developments are in preferred embodiments.
According to certain preferred embodiments of the invention, an arrangement is suggested which, in the event of the occurrence of a brief excessively high loading of the torsion bar spring arrangement, protects the latter in that the introduction of force is reduced to the maximal value of the normal load. This arrangement comprises at least one prestressed spring element. This prestressing is selected such that, in the case of the maximally occurring normal loading of the torsion bar or stabilizer arrangement, the spring element transmits the affecting force unchanged whereas, in the case of a so-called overload, which occurs only briefly in the form of a momentum or the like, the spring element will deform, whereby the torsion bar spring arrangement or the torsion bar or stabilizer are not acted upon by this overload momentum. The loading of the torsion bar spring arrangement is therefore reduced to the normal amount defined by the prestressing force of the spring element.
As mentioned above, this suggested measure is particularly helpful for a so-called active chassis of a motor vehicle, in which case a stabilizer (or generally a torsion bar spring) has a divided construction and the (two) parts of the stabilizer (or of the torsion bar spring) can be rotated with respect to one another by way of an actuator or servo motor, as illustrated, for example, in German Patent Document DE 44 43 809 A1. In this case, not only such an actuator but the entire stabilizer arrangement can be designed or dimensioned on the basis of arbitrary marginal conditions such that the limit of the mechanical loading (for example, also with respect to the strength of the material of the stabilizer itself, but particularly with respect to the torque load of the actuator or servo motor) is reached specifically in an extreme driving operation. So far, it had been necessary in this case to design the stabilizer or torsion bar spring arrangement not only for the highest possible load with respect to driving dynamics but even for taking into account an additional load (in the following, called xe2x80x9coverloadxe2x80x9d) which occurs, for example, as a result of the exceeding of a threshold or the like. So far, such events had to be taken into account when designing the system with respect to the forces, although cases in which such an extreme loading occurs with a simultaneous overload, that is, such a high introduction of force, are extremely rare.
In contrast, by way of certain preferred embodiments of the present invention, the system or the stabilizer or torsion bar spring arrangement has to be designed only for the normal maximal load. If a still higher momentum-type, that is, brief introduction of force, takes place, this additional force exceeding the prestressing force of the spring element, the spring element will be compressed so that this overload occurring only briefly in the form of a momentum will be kept away from the stabilizer or from an actuator or servo motor provided in the system or in the arrangement.
It is pointed out that a spring element operating as an overload protection and therefore also called an overload spring can basically be inserted in an appropriately divided stabilizer while the latter is not provided with an actuator because a single prestressed spring element according to certain preferred embodiments of the invention is sufficient. In contrast, in the case of an arrangement according to the above-mentioned European Patent Document EP 0 648 625 A1, two overload spring elements of this type are required.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.